The present invention relates to a semiconductor device, and more particularly, to a semiconductor heterostructure laser which generates a high-frequency laser beam.
To obtain a high-frequency laser beam in the visible light region, a technique has been recently used in which the frequency of the laser beam generated from a light source such as a laser diode is doubled. An optically nonlinear crystal has been conventionally used as the structure for doubling the frequency.
However, this optically nonlinear crystal cannot efficiently perform the frequency doubling, due to the mismatch between the light source and the optically nonlinear crystal.